dan22644
10-06-2010, 12:40 PM
I wanted to start a new thread because the last one was just about getting some replacement fuel injectors, and now it has turned into a lot more. Here is the old thread for reference:
http://forums.bimmerforums.com/forum/showthread.php?t=1467117
To update, I am still getting the following codes when the engine is above about 3200 to 3500 rpm for more than a second or two:
P1341 Multiple Cylinder Misfire With Fuel Cut-off
P1343 Misfire Cylinder 1 With Fuel Cut-off
P1353 Misfire Cylinder 6 With Fuel Cut-off
P1355 Misfire Cylinder 7 With Fuel Cut-off
P1365 Misfire Cylinder 12 With Fuel Cut-off
Since my last update, I took the intakes off and re-sealed to try and find a possible vacuum leak and to also reseat and check all connection and vacuum lines. Everything came out really nice, but the codes remained. I have also replaced the caps and rotors.
At this point I didn’t know what to do, so I took it to BMW and asked for a diagnostic. I authorized 1 hour of labor for their work. Three days later they called me and said that they performed a vacuum leak test and didn’t find anything, and checked the computer and all sensor data and didn’t see anything out of the ordinary. They were able to re-create the codes on demand, but were not able to identify a reason why.
They wanted me to authorize another hour of labor to do a more in-depth look at the ignition system. I agreed if they would also test my cats (and a couple other small unrelated issues). The test showed that my plug wires were good, my coils were good, fuel pressure was correct, and that my pre-cat backpressure was on 0.5 PSI which is perfect.
They had the car a total of 2 weeks and even brought in their technician trainer to look at it. His best guess was to replace the rubber boots on the intake manifolds (part number 8 and 9 below).
http://www.realoem.com/bmw/showparts.do?model=GJ03&mospid=48546&btnr=11_1515&hg=11&fg=40
Because they couldn’t tell me exactly what was wrong, they did not charge me for their work! They even told me to bring the car back if this didn’t solve the problem, and if it did to let them know that it worked.
Since then, I was able to locate the rubber boots for $100 each with a discount coupon, so I dropped $400 and tried to gear myself up to do this job again.
I took a day off of work and tore the thing apart. When removing the rubber boots from the cylinder head, I was surprised to see that there was no sealant used. The little rubber ridge didn’t look like very good on the end cylinders, so I thought I may be on to something. I used Hylomar to seal between the boot and the head, and the boot to the manifold runner. Reassemble everything and test drive, same misfire codes :(
To date, parts that have been replaced:
new OSVs
new OSV rubber grommets
new throttle body gaskets
new valve cover gaskets
new intake rubber boots sealed with Hylomar
new plugs
new caps and rotors
new camshaft position sensor
new pre-cat O2 sensors
new fuel filter
cleaned the MAFs
cleaned and tested the crank position sensor
cleaned and flow tested fuel injectors
One of the problems that BMW pointed out to me while I had it was that my Secondary Air pump hoses were all shot, one was actually worn through. I had planned on replacing them, but I had an idea last night. On startup the engine is a little noisy because the exhaust can be heard through the secondary air system hoses. If I had a valve stuck open on in the secondary air system (part 1)
http://www.realoem.com/bmw/showparts.do?model=GJ03&mospid=48546&btnr=11_1496&hg=11&fg=50
then I would have an air leak into the exhaust. Maybe that could cause the O2 sensor to get far enough out of range that I get a misfire??? To test this theory, I removed the hoses 20 and 21
http://www.realoem.com/bmw/showparts.do?model=GJ03&mospid=48546&btnr=11_1495&hg=11&fg=50
and plugged the valves with silicon plugs and taped them in place. When I started the engine it was perfectly quiet, but I still got the code above 3500rpm :(
I am really running out of ideas. I think my next test will be to swap some plug wires and see if the codes move to other cylinders. I need to replace them anyway since I’m over 100,000 but I would like to KNOW what the problem is before spending anymore money.
http://forums.bimmerforums.com/forum/showthread.php?t=1467117
To update, I am still getting the following codes when the engine is above about 3200 to 3500 rpm for more than a second or two:
P1341 Multiple Cylinder Misfire With Fuel Cut-off
P1343 Misfire Cylinder 1 With Fuel Cut-off
P1353 Misfire Cylinder 6 With Fuel Cut-off
P1355 Misfire Cylinder 7 With Fuel Cut-off
P1365 Misfire Cylinder 12 With Fuel Cut-off
Since my last update, I took the intakes off and re-sealed to try and find a possible vacuum leak and to also reseat and check all connection and vacuum lines. Everything came out really nice, but the codes remained. I have also replaced the caps and rotors.
At this point I didn’t know what to do, so I took it to BMW and asked for a diagnostic. I authorized 1 hour of labor for their work. Three days later they called me and said that they performed a vacuum leak test and didn’t find anything, and checked the computer and all sensor data and didn’t see anything out of the ordinary. They were able to re-create the codes on demand, but were not able to identify a reason why.
They wanted me to authorize another hour of labor to do a more in-depth look at the ignition system. I agreed if they would also test my cats (and a couple other small unrelated issues). The test showed that my plug wires were good, my coils were good, fuel pressure was correct, and that my pre-cat backpressure was on 0.5 PSI which is perfect.
They had the car a total of 2 weeks and even brought in their technician trainer to look at it. His best guess was to replace the rubber boots on the intake manifolds (part number 8 and 9 below).
http://www.realoem.com/bmw/showparts.do?model=GJ03&mospid=48546&btnr=11_1515&hg=11&fg=40
Because they couldn’t tell me exactly what was wrong, they did not charge me for their work! They even told me to bring the car back if this didn’t solve the problem, and if it did to let them know that it worked.
Since then, I was able to locate the rubber boots for $100 each with a discount coupon, so I dropped $400 and tried to gear myself up to do this job again.
I took a day off of work and tore the thing apart. When removing the rubber boots from the cylinder head, I was surprised to see that there was no sealant used. The little rubber ridge didn’t look like very good on the end cylinders, so I thought I may be on to something. I used Hylomar to seal between the boot and the head, and the boot to the manifold runner. Reassemble everything and test drive, same misfire codes :(
To date, parts that have been replaced:
new OSVs
new OSV rubber grommets
new throttle body gaskets
new valve cover gaskets
new intake rubber boots sealed with Hylomar
new plugs
new caps and rotors
new camshaft position sensor
new pre-cat O2 sensors
new fuel filter
cleaned the MAFs
cleaned and tested the crank position sensor
cleaned and flow tested fuel injectors
One of the problems that BMW pointed out to me while I had it was that my Secondary Air pump hoses were all shot, one was actually worn through. I had planned on replacing them, but I had an idea last night. On startup the engine is a little noisy because the exhaust can be heard through the secondary air system hoses. If I had a valve stuck open on in the secondary air system (part 1)
http://www.realoem.com/bmw/showparts.do?model=GJ03&mospid=48546&btnr=11_1496&hg=11&fg=50
then I would have an air leak into the exhaust. Maybe that could cause the O2 sensor to get far enough out of range that I get a misfire??? To test this theory, I removed the hoses 20 and 21
http://www.realoem.com/bmw/showparts.do?model=GJ03&mospid=48546&btnr=11_1495&hg=11&fg=50
and plugged the valves with silicon plugs and taped them in place. When I started the engine it was perfectly quiet, but I still got the code above 3500rpm :(
I am really running out of ideas. I think my next test will be to swap some plug wires and see if the codes move to other cylinders. I need to replace them anyway since I’m over 100,000 but I would like to KNOW what the problem is before spending anymore money.